Lighting systems (such as headlights) are well-known and are used in a wide variety of applications, including automotive applications. In general, a lighting system includes one or more projector apparatus for emitting light distinct patterns. For example, a lighting system may emit light in a low-beam mode in which light is generally emitted below the horizon. The lighting system may also emit light in a high beam mode in which light is generally emitted above and below the horizon. Recently, lighting systems have also begun to emit light in a daytime running lights (DRL) mode in order to increase the visibility of the vehicle during daylight conditions. In a DRL mode, light is emitted above and below the horizon, however, the light is typically emitted at a lower overall output compared to either the low and/or high beam modes (for example, in order to comply with SAE regulations or ECE specifications). Examples of such lighting system may be found in U.S. Pat. No. 7,316,492 (Yamamura), U.S. Patent Pub. No. 2009/0097269 (Stauss); U.S. Patent Pub. No. 2004/0240221 (Choi); U.S. Patent Pub. No. 2006/0002128 (Suzuki); U.S. Patent Pub. No. 2004/0228137 (Mensales); U.S. Patent Pub. No. 2008/0037269 (Sugiyama); U.S. Patent Pub. No. 2005/0073853 (Stam); U.S. Patent Pub. No. 2008/0037270 (Kagiyama); U.S. Pat. No. 6,467,940 (Eschler); and U.S. Pat. No. 6,976,772 (Albou).
In many applications, it may be desirable for the low and/or high beam mode to utilize a halogen lamp or a high-intensity discharge (HID) light source. Unfortunately, it is generally not possible to operate HID light sources at reduced voltages (power) compared to their designed, steady-state operating voltages. Similarly, while it may be possible to operate halogens at reduced power levels, halogens are typically not very efficient below their designed, steady-state operating powers, particularly ECE specifications due to the high dimming ratio necessary. One approach to address these issues has been to provide a separate, dedicated lighting apparatus designed to function only in the DRL mode. Unfortunately, such an approach increases the costs since two lighting apparatus must be provided for each side of the vehicle. In addition, operating a single lighting source in both DRL mode as well as low/high beam mode may significantly shorten the lifespan of the lighting source since the light source would be operating continuously while the vehicle is running.